Automatic safety



1,640,045 A 1927' B. MATSON AUTOMATIC SAFETY APPLIANCE FOR ,GAS BURNERSFiled 001:. 1925 INVENTQR Wrrmasaas 74m Patented Aug. 23, 1927.

UNITED STATES MARCUS B. MATBON, OF NEW YORK, N. Y.

AUTOMATIC SAFETY APPLIANCE FOR GAS BURNEBS.

Application filed October 30, 1925. Serial No. 85,867.

This invention relates to a thermo-electrically controlled gas cut-oftvalve which controls the flow of gas to one or more gas burners orfixtures and is an improvement over the subject matter of my pendingapplication Serial No. 41,864, series of 1925, filed July 6th, 1925, inwhich the cut-off valve control is achieved thermo-mechanically. Thecontrol described in my pending application is desirable where thecontrol of gas for but a single burner is contemplated. My presentinvention is desirable and practical when the control of gas to abattery of burners or gas fixtures is contemplated. Both inventionsrender it impossible for unignited gas to flow from aburner.

The principal object of this invention is the prevention of accidentalasphyxiations and the deterrence of suicide from gas appliances.

Another object of my invention is to provide an extremely simple,inexpensive, and positively acting automatic appliance for stopping theflow of fuel to a fuel burning fixture, or the like, whenever thefixture cock is set to permit the fiow of fuel therethrough and the fuelis not burning at the fixture.

A further object of my invention is t provide an appliance of thecharacter described which operates on electric current and requires onlya single circuit and a minimum number of circuit making and breakingdevices or other movable parts.

A further object is the provision of a cut-- off valve, the operation ofwhich may be retarded to allow the operator sufficient time to light theburner after turning on the cock, before said cut-off valve closescompletely. This timing is accomplished by varying the electricalresistance of the heating element surrounding the valve and byregulating the ventilation of the protective housing that encloses boththe heating element and the valve.

A. still further object of my invention lies in the fact that the deviceis completely automatic: it functions only in an emergency whenunignited gas is flowing from a burner. No change whatever fromcustomary methods is necessitated in the operation of the fixtures.disordered and is fool-proof. Current con: sumption is negligible andcost of manufacture is small.

The device is not easily In accordance with my invention, I proylde inthe fuel supply pipe to a fuel burnmg fixture, or the like, an electricsafety shut-off valve which is controlled by two electric switches, oneof which is thermally controlled by flame conditions at the fixture andthe other of which is controlled by the ad ustment of the cock of thefixture. I prefer to place these switches in series in the circuit whichoperates the shut-off valve, thus requiring only a single circuit forthe safety appliance. The thermal switch at the fixture is preferably ofthe snap action type and its electrical contacts are shielded from theheat of the flame and from dust, dirt, grease, and the like, which mightcause improper contact at the terminals and otherwise interfere with thepositive operation of the switch. As illustrative of an apparatus forcarrylng my present invention into effect, reference is made to theaccompanying drawing, in which:'

Fig. 1 is a diagrammatic view of the invention. adapted to a single gasburner of the range type. It is evident, however, from the constructionshown, that the device may be extended to cover a plurality of burnersor fixtures.

Fig. 2 is a detailed view of the gas cut-off valve.

Fig. 3 is a cross-sectional view on the line 33 of Figure 2.

Fig. 4 is a diagrammatic view of another type of thermo-electric contactthan that included in Figure 1.

In Figure 1 of the drawing there is shown a burner 1 with air control 7and gas cook 10 connected to supply manifold 13. Manifold 13 may beextended to supply gas to a plurality of other burners. Installed at apoint on the supply main before the gas is diverted through cocks to anyof the burners or fixtures is a gas cut-off valve, comprising, generallya container 16 filled with a suitable thermal medium 29 (usually ahydro-carbon oil), a piece of corrugated expanding and contractingtubing 30 made tight to cap 21. rod 23 and valve gate 24 by solderedconnections 22. Also provided is filling plug 17, valve structure 15with valve seat 25 and heating element 14 surrounding container 16 andinsulated therefrom by strips 20. Protective housings 27 and 28 whichare secured by means 31 to container 16 have adjustable Ill) ' stripports to vent excess heat, and, enclose heating element 14 and thermalcontainer 16. Supply main 26 and supply manifold 13 are attached asshown to the cut-off valve.

Installed in the main line 19 is a switch 18 to be used only in theevent of a part of the device failin to function.

To manifo d 13 is fastened clamp 12 which contains insulated contactstrip 8. To the bottom part of the core of gas cock 10 s fastenedsupport 11 in such a manner that it will move angularly the same as gascock handle 29 when same is manually actuated. Secured to support 11 isinsulated contact Exposed to the heat from burner 1 is thermal disc 2embodied in structure 6 which is clampedin proper position, in relationto the heat, to burner 1. To thermal disc 2 by means of rod 3, isfastened contact disc 5 with adjustment means 30. Fastened to andinsulated from structure 6 are contacts 4.

Thermal disc 2 is designed to flip from concave to convex position whena temperature of approximately 200 F. is exceeded and conversely to flipback to concave position when the temperature falls below this point.When the burner is not lighted and the temperature is below 200 F. thedisc 2 is in concave position and the circuit is completed at this pointthrough contact disc 5 and contact points 4. When the burner is lightedand the temperature surrounding the disc 2, even at a very low flame,exceeds 200 F. The disc is in convex position and the circuit is brokenby the automatic removal of contact disc 5 from contact points 4.

Figure 4 discloses another type of thermoelectric contact at the burner.In the figure, strips 33 and 34; are metals possessing differentcoeflicients of expansion fastened together by means 35 and made rigidto the burner at the base 36. Piece 32 is secured to but insulated from(except at point of contact 37) strips 33 and 34. When heat is appliedto this portion of the apparatus the strips 33 and 34 will expand awayfrom piece 32 breaking contact, at point of contact 37, in the circuit.Additionally, there are numerous other ways of accomplishing thisthemo-electrical contact not shown on the drawing nor described in thisspecification. the two methods shown merely being deemed best suited forthe device.

\Vhen gas cock 10 is in off position as shown in Fig. 1, the circuit atthis point is broken. lVhen, however, it is turned to any part of onposition, the circuit is completed through contact strips 8 and 9.

In operation the device functions as followszf In the ordinary mannerthe gas cock is turned to on position preparatory to lighting theburner. This operation completes the electric circuit controlling thatparticular burner, it being remembered that heat is required at theburner to break the same circuit thermostaticall by means of thermaldisc 2. Immediatey upon turning on the cock heat is generated in heatingelement 14 which in turn expands the thermal medium 29 forcing towardclosed position the valve gate 24 by the enforced compression ofexpanding and contracting tube 30. If, however, the gas at the burner isignited before the time interval that exists between the moment thecircuit is completed and the valve commences to close and the moment thevalve is completely closed, elapses, the heat generated by such ignitionof the gas will thermostatically break the circuit at the burner and thevalve will not close; the burner, therefore, functioning as intended.

Should the flame become extinguished for any reason whatever other thanthat of purposely turning off the cock, the thermal disc 2 willautomatically complete the circuit again and the valve will shut off thesupply of gas. Or should a child, for example, approach an unignitedburner and turn the cock to on position, the circuit would be completedand the valve would close. Thus it is seen that unignited gas cannotflow from the burner.

I am aware that other devices purporting to accomplish the ends aboveset forth have been designed and experimented with but none have evermerited extensive usage because of their costly adaptation to standardequipment, because they were not sufficiently automatic, because ofbulky size and because they were easily disordered and not at allpositive of operation. My invention overcomes each of these obstaclesand can be applied at low cost to all gas fixtures in an entirehousehold.

As many changes could be made in the above construction and as manyapparently widely different embodiments of this invention could be madewithout departing from the scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingsshall be interpreted as illustrative and not in a limiting sense.

lVhat I claim as new and desire to secure by Letters Patent of theUnited States is:

1. The combination with a fuel burning fixture having a control cock, afuel supply conduit to the fixture, and a safety shut-off valve in saidconduit, of means, including an electric actuating circuit, foradjusting said valve, and means for opening and closing said circuit tocontrol the. adjustment of said valve. said means including a thermallyoperated snap action switch controlled by flame conditions at thefixture, and another switch controlled by movement of the fixture cock.

2. The combination with a fuel burning fixture having a control cock, afuel supply conduit to the fixture, and a safety shut-off valve in saidconduit, of means, including an electric actuating circuit. foradjusting said valve, and means for opening and clo:- iugsaid circuit tocontrol the adjustment of said valve, said means including a thermallyoperated switch in said circuit controlled by flame conditions at thefixture, and another switch controlled by movement of the fixture cock.

3. The combination with a fuel burning fixture having a control cook, afuel supply conduit to the fixture, and a safety shut-off valve in saidconduit, of means, including an electric actuating circuit, foradjusting said valve, and means i' or opening and closing said circuitto control the adjustment of said valve, said means including athermally operated snap action switch in said circuit controlled byflame conditions at the -fixture, and another switch controlled bymovement ofthe fixture cock.

4. The combination with a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of means for shutting off thesupply of fuel to the fixture through said conduit when the cock is inadjustment to pass fuel and the fuel is not burning at the fixture,saidmeans including a thermally operated shut-off valve in said conduit,and an electric heating device for supplying heat to operate said valve.

5. The combination with a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of means for shutting off thesupply of fuel to the fixture through said conduit when the cock is inadjustment to pass fuel and the fuel is not burning at the fixture, saidmeans including .a thermally operated shut-off valve in said conduit, anelectric heating device for supplying heat to operate said valve, anelectric circuit for said heating device, a thermally operated switchcontrolled by flame conditions at the fixture, and another switchcontrolled by adjustment of the fixture cock.

6. The combination with a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of means for shutting off thesupply of fuel to the fixture through said conduit when the cock is inadjustment to pass fuel and the fuel is not burning at the fixture, saidmeans including a thermally operated shut-off valve in said conduit. anelectric heating device for supplying heat to operate said valve. anelectric circuit for said heating device. a thermally operated switchcontrolled by flame conditions at the fixture, and another switchcontrolled by adjustment of the fixture cock, said switches being inseries in said heating device circuit.

7. The combination with a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of a thermo-electricallyoperated valve, including an electric actuating circuit, for shuttingoff the flow of fuel to said fixture, and means for opening and closingsaid circuit to control the adjustment of said valve, said meansincluding an electric switch thermally actuated by flame conditions atthe burner, and another switch actuated by movement of said fixturecock.

8. The combination wit-h a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of a thermoelectricallyoperated valve, including an electric actuating circuit. for shuttingoff the flow of fuel to said fixture, and means for opening and closingsaid circuit to control the adjustment of said valve, said meansincluding an electric switch thermally actuated by flame conditions atthe burner, and another switch actuated by movement of said fixturecock, said switches being in series relation in said valve actuatingcircuit.

9. The combination with a fuel burning fixture having a control cock,and a fuel supply conduit to the fixture, of a thermo-electricallyoperated valve, including an electric actuating circuit, for shuttingoff the flow of fuel to said fixture, two electric switches in series insaid circuit, means thermally responsive to flame conditions at thefixture for operating one of said switches, and means responsive tomovement of the fixture cock for, operating the other of said switches.whereby said valve operating circuit is closed to cause said valve toshut off the supply of fuel to the fixture whenever the fixture cock isin position to allow fuel to pass and there is no corresponding flame atthe fixture.

10. In a thermostatic control, including a container supplied withmaterial expansible under the influence of heat, and a device adjacentthe container for heating the same, a protective housing enclosing saidcontainer and heating device, said housing having adustable vents,whereby the heating of said container by said heating device maybecontrolled in accordance with the amount of ventilation afforded by theadjustment of said vents.

11. In a thermostatic control. including a container supplied withmaterial expansiblc under the influence of heat. an electric heatingcoil surrounding the container for heat.- ing the same, a protectivehousing enclosing said container and coil. and adjustable vents in saidhousing. affording ventilation to said coil and container in accordancewith the adjustment of said vents.

In testimony whereof I allix my signature.

MARCUS B. MATSON.

